The subject application discloses a threader tube assembly which, while having utility in tufting systems generally, is particularly adaptable to tufting procedures of the "Spanel tufting system."
The fundamentals of the "Spanel tufting system" are disclosed in U.S. Pat. No. 3,554,147 which issued to Abram N. Spanel and George J. Brennan on Jan. 12, 1971 and U.S. Pat. No. Re. 27,165 which issued Aug. 10, 1971 to Abram N. Spanel and Lloyd E. Barton.
As disclosed in U.S. Pat. No. Re. 27,165, a pneumatic yarn transport system is disclosed wherein yarn strands and/or discrete bits of yarn are transported pneumatically to a tufting station where they are applied by tufting elements to a backing layer. Multicolor selection of the yarn bits is enabled by a shiftable magazine arrangement which provides yarn strands of various colors to each of the guide tubes through which yarn is transported to the tufting elements. For each tufting element, there is a single common guide tube passageway that extends from the magazine and through which the yarn strand or yarn bit is pneumatically fed.
The aforementioned U.S. Pat. No. 3,554,147 provides for the simultaneous selection of bit-lengths of yarn of various colors for each tufting cycle at each individual tufting station. In place of the magazine of U.S. Pat. No. Re. 27,165, U.S. Pat. No. 3,554,147 uses a collator structure in which individual channels transport yarn into a common passageway adjacent the tufting station. Each of the tufting elements has a corresponding single such common passageway leading to it through which the yarn strand is delivered prior to tufting. The capability of severing a bit-length of yarn before, during or after threading the tufting element and before or during actual tufting is provided. Since a common passageway is utilized, and since in one embodiment the severing function takes place adjacent the location of the tufting elements and after a selected yarn strand has been fed into the common passageway, a yarn pullback system is provided to remove the remaining yarn strand from the common passageway once the yarn bit has been severed therefrom.
Additionally, copending Spanel application Ser. No. 419,417 discloses improvements to the earlier Spanel disclosures in which a cutting arrangement is utilized whereby an axially reciprocable passageway section provides access for yarn severing means to sever the yarn into preselected discrete yarn bit-lengths.
Furthermore, Spanel U.S. Pat. No. 3,824,939 discloses tufting apparatus which utilizes a reciprocable threader tube having a single common passageway corresponding to each tufting needle, to place yarn in the eye of the needle and which retracts to leave the yarn deposited therein. Pneumatic means supplements the yarn transportation system.
Finally, Spanel application Ser. No. 474,264 and Ser. No. 474,266, filed concurrently with the subject application disclose additional improvements and modifications to the earlier Spanel disclosures. The first of the abovementioned applications discloses improved feeding, metering and pullback systems including improved valvable air supply means. A common passageway is, however, utilized to guide the selected yarn strand to the loading station where it is severed into a bit-length of yarn to be tufted.
With respect to Spanel application Ser. No. 474,266, various embodiments of yarn bit clamps are disclosed which may be utilized with any of the aforementioned Spanel disclosures.
In all of the above disclosures, a common passageway is used for delivering the yarn strand or bit-length of yarn to the tufting station. With such structure, it is necessary to either provide for yarn strand severing into a bit-length before the yarn enters into the common passageway or to provide for severing while in the common passageway together with withdrawal of the remaining yarn from the common passageway.